Prediction of Japanese cedar pollen emission in a snowy area--surveillance in Hirosaki City

Abstract

Japanese cedar is the most common pollinosis allergen in Japan. Predictions of total pollen counts and the first 2 or more days of the Japanese cedar pollen season are beneficial to patients. We developed predictive methods for those 2 factors in Hirosaki. We conducted an atmospheric Japanese cedar pollen survey from 1996 to 2002 in Hirosaki and compared yearly data with the male flowering index counted in 50 cedar trees in the preceding autumn. The male flowering index correlated highly positively with total cedar pollen counts in regression analysis, indicating its usefulness in predicting total pollen counts. Although the number of days from January 1 to the first day of continuous pollen emission showed no correlation with the cumulative maximum temperature during these days, the number of days from the day of first detection of pollen emission (minimum of 1 particle per sq. cm) to the first day of continuous pollen emission correlated highly with the cumulative maximum temperature and cumulative amount of snowfall on these days, suggesting that it is possible to predict the first day of continuous pollen emission by the cumulated daily maximum temperature after the day of first detection of pollen emission.